Mercury switch



June 29, 1937. K. HUNCIKER MERCURY SWITCH Filed April 12, 19:53

FIB!

INVENTOR KARL HUNGIKER BY 4 Fig.5

Patented June 29, 1937 UNITED STATES PATENT- orr cs MERCURY SWITCH KarlHunciker, Chicago, 111., assignor to In E.

McCabe, Chicago, Ill.

Application April 12, 1933, Serial No. 665,628

Claims.

This invention relates to improvements in mercury switches and moreparticularly to that type of mercury switch in which the tube andcontained mercury remains stationary and move- 5 ment is imparted toelements also contained within the tube to make and break the circuittherein.

The mercury tube switch comprising a sealed tube or envelope, usually ofglass, containing a movable body of mercury and an inert gas havingspaced apart electrodes sealed in the walls and entering the interior sothat upon tilting the mercury is' caused to flow from end to end toclose and open the circuit between the electrodes is a commercialproduct well known in the switch art.

It is an object of this invention to produce a but a small amount ofmercury and in which the tube and mercury remain stationary while one ormore of the electrodes are caused to move into and out of contact withthe mercury to make 'and break' the circuit therein, thereby not onlymaking a saving in the cost of the mercury employed but also obviatingthe internal stresses g5 and strains upon the tube heretofore caused bythe mercury hammer in the tilting tube type.

It is also an object of this invention to actuate one or more of theelectrodes by magnetic force, thereby obviating the necessity of amechanical 3o snap movement heretofore used in the rapid tilting of thetube to throw the mercury from one position to another, and allowmercury tube switches to be employed under conditions where snap actionswitches would be impracticable.

With these and other objects in view reference is made to theaccompanying sheet of drawings which illustrates preferred embodimentsof this invention with the understanding that minor detail changes maybe made therein with out departing from the scope thereof. In thedrawing- Figure 1 is a vertical central sectional view, with parts shownin front elevation, of one form of this invention. 4.5 Figure 2 is aview partly in side elevation and partly in central vertical section ofFigure 1.

Figure 3 is a view similar to Figure 1 of a modification. A

Figure 4 is a view similar to Figure 2 of Figure 3. Figure 5 is a viewsimilar to Figure 1 of another modification.

Figure B is a view similar to Figure 1 of a further modification.

Figure '7 is a view similar to Figure 1' of a 55 still furthermodification.

switch of this general character which requires envelope or tubel,closed at the lower end pref-. .10

erably to form a' depending'pocket or cup 2 adapted to receive andretain a small body of mercury or other vfluid electrical conductor 8.The upper end is preferably closed by a pinch seal which embraces andsealsin the body thereof 15 one or o e leadin r n wires 4 and a fillingstein c 5 through which the gas is substituted for the contained air,mercury inserted and the start: then tipped off. The leading-in wiresare of such character as to seal readily in the body'cf the envelope 420 wires. 1 r

In Figures 1 and 2. one electrode 8 is inn form of a rigid wire whichextends from its leading-in wire to engage the mercur g "11:

cup 2 and is terminated below the surface thereof. The other electrode 1is preferably flattened, as shown in Figure 2, and corrugated or fluted:adjacent its leading-in wire as at I to'increase its flexibility andresiliency and then extended .1

over the mercury I and terminated in a bent; 35 down end 8 normally outof contact 'with the 1 mercury I, so formed that the-bend is normally;spaced a lesser distance from the tube 1 than v ,,:-'j Y the distance ofthe extremity 8 from the mercury 3. That part of theelectrode betweenthe corru- 40 gation 8 and extension which passes over the mercury 3supports a preferably semi-cylindrical f section or member ll of.magnetic meta l, spacedapart from the wall of the tube! andadapted torespond as an armature when affectedby the 45""- field of a magnet, suchas the fixed magnet ll shown inFigurel, so that when e magnet is broughtsumciently close to the tube l the armature is caused to move toward itflexing the portion 8 or the electrode 1 until the armature ll contactsthe wall'ofthe tube and such movement causes the end 9 of the electrode,1 to contact and enter the mercury Lthereby closing the circuit throughthe switch. when the magnet is moved away tube 1, the pullonthe armatureIII is released and the electrode I straightens out to remove the end 9from the mercury and thereby break the circuit.

While a fixed magnet is shown by way of example, an electro-magnet maybe employed which may be stationary, if desired, with means to energizeit when it is desired to close the circuit. When it is desired to use afixed magnet, such as II, any desired means may be employed toreciprocate it toward and away from the tube I.

In the form shown in. Figures 3 and 4, one electrode Ia is corrugated orfluted to provide resilient flexibility, and supports a magnetic memberID, in the same manner as shown in Figures 1 and 2, however, the portionextending over the mercury passes through an insulating material yoke I2before terminating in the bent down end 9 normally out of contact withthe mercury 3. The other electrode I3 is also preferably flattened andcorrugated or fluted at 811 adjacent its leading-in wire to provideresilient flexibility then terminates in a round portion passing throughthe yoke I2 spaced apart from the other electrode and ends in a portionI4 parallel to the end 9 of the other and also normally out of contactwith the mercury 3.

In this form when the armature is actuated by a magnet to move in thedirection of the adjacent wall of the tube I both ends 9 and I4 are, bymeans of the yoke I2, brought into contact with the mercury 3 to closethe circuit therethrough and when the magnetic force is removed thearmature I0 is released and the corrugated or fluted portions 8 and 8astraighten out, removing the ends 9 and I4 from the mercury to break thecircuit.

In the form shown in Figure 5, one leading-in .wire 4 passes through thepinch seal and another 4a is sealed in the wall of the pocket 2 to whichis welded or otherwise secured a short electrode I5 which is alwayssubmerged in the mercury 3, the other electrode 11) is Welded orotherwise socured to the leading-in wire 4, is corrugated or fluted, asat 8, adjacent thereto to provide resilient flexibility and supports amagnetic memb r III in the same manner as shown in Figure 1. In thisform the electrode Ib terminates in an end I 3 which normallycontacts'the mercury 3 and enters below the surface thereof, therebycompleting the circuit through the switch.

When a magnetic force is applied to draw the armature I0 toward theadjacent wall of the tube I, the end I8 of the electrode 1b iswithdrawn. out of contact with the mercury to break the circuit, asshown in Figure 5.

In the form illustrated in Figure 6, the electrode 1b is constructed inthe manner shown in Figure 5 with the end I6 normally in contact withthe mercury 3 and the electrode I3 constructed in the manner shown inFigure 3 with the end I4 normally out of contact with the mercury 3, thetwo ends I4 and I6 passing through the yoke I2 holding them in spacedrelation and when the armature I0 is drawn toward the adjacent, wall ofthe tube I, the end I6 is moved out of contact with the mercury 3 and.through the yoke I2 the end I I is moved into contact with the saidmercury. Since the electrode I5 01 the leading-in wire 4a is always incontact with the mercury 3, a circuit is always closed through theswitch from the electrode I5 through either electrode lb or electrodeI3, depending upon the actuation of the armature III.

Figure '7 illustrates a modification in which the electrodes 1c and I3aare both flattened to produce resilient flexibility and the electrode 10is preferably provided with one corrugation or fluted portion 8b to addto its flexibility, otherwise, they are both of the same construction asshown in Figures 3 and 4 with the ends passing through the yoke I2 andboth normally out of contact with the mercury 3. In this form theleading-in wire la is sealed in the walls of the pocket 2 and supportsthe electrode I5 always submerged in the mercury 3, so that when thecircuit is closed the current flowing from electrode I5 divides andpasses through the electrodes I0 and I 3a.

Figure 8 illustrates another form of this general type of switchillustrating the application of this principle to two actuating means.In this instance, the electrode Ib is constructed in the same manner asshown in Figure 5 and the electrode I3b is corrugated or provided with afluted portion 8a to provide resilient flexibility and therebelowsupports a magnetic member Illa similar to the member III, and the endI! is bent to normally terminate above and out of contact with themercury 3, as shown in full lines. Under normal conditions, that is whenthe switch is removed from the influence of an electromagnetic field,and the armature IOa attracted by the magnet II, the electrode ID willthrough its end I6 contact the mercury 3, while the end I I of the otherelectrode I 30. will be out of contact with the mercury so that thecircuit is broken within the tube I.

This switch is of particular use where one magnet II will normallyoperate to open and close the circuit through the switch and anothermagnet IIa, such as an electro-magnet, may be employed, when energizedto openthe circuit when closed by the magnet II by withdrawing the endI6 out of the mercury. An example of such use may be found in a controlsystem for an electrically operated and controlled fluid fuel burnermechanism when the magnet II may be reciprocated to close and open theburner motor circuit, or a control circuit thereof, by a room thermostatand the other magnet IIa being an electro-magnet, as shown, may beconnected in a circuit containing a commercial boiler control responsiveto interior conditions of the boiler which circuit is normally open inthe boiler control but which is caused to close upon excessivetemperature or pressure within the boiler. The energization of themagnet I I a will draw the armature I0 towards the adjacent wall or thetube I and withdraw the end I6 01' the electrode ID from the mercury 3and maintain it out of contact irrespective of the position of themagnet II until the conditions within the boiler become normal and thecircuit again opened within the boiler control.

In the form illustrated in Figure 9, one electrode 6 is similar to theone shown in Figure 1, and terminates below the surface of the mercury 3while the other is so formed to support the armature I 0 independently'of the resilient flexible portion. In order to accomplish this, theelectrode Id is provided with an offset 10 between its leading-in wire 4and the flattened and corrugated or fluted portion 8 formed to normallymaintain its end I8 out of contact with the mercury 3. The upper portionof the armature I0 is provided with ears Illa pivotally mounted upon avertical support I9 depending from the offset 10 and the lower portionwith a forked extension Illb, as shown, adapted to embrace the end I8 ofthe electrode and normally hold the armature I0 against the end 20 ofthe support I9, whereby the weight of the armature acts as a stabilizerin the event of vibration of the switch mounting.

,There have been many types of magnetic tubes used such as disclosed bythe Hatfield Patent No. 1,094,440 and the Hewitt Patent No. 1,110,548wherein the armature is used to bridge two pools of mercury or asdisclosed in the Keyes Patent No. 1,461,038 and the Phelan et al. PatentNo. 1,558,277, wherein the armature is pivoted and swung.

These latter types ofler difliculties in that the current must becarried between the bearings and arcing occurs causing unsatisfactoryand unreliable performance since the surface which must act as a pivotmay become pitted, welded or otherwise deformed or defaced as to makeunsatisfactory contact or an unsatisfactory bearing.

This invention overcomes the weakness and difficulties of the prior artand will perform the requirements of such a switch satisfactorily.

It is also possible with this type of construction, as evident in Figure1, to insure the opening of the circuit through the switch upon failureof the magnetic field or failure of the magnet operating mechanism, andfurther the flexible armature carrying electrode may be made resilientenough to prevent its movement by gravity, to make or break contact withthe mercury, should the switch be tilted out of vertical position whennot under the influence of the magnetic field. As the body of mercury issmall and well contained in the'cup and with its natural tendency toadhere to the glass it requires considerable rotation of the switch toshift the position of the mercury so that, except in extreme cases,rotation from the vertical will not effect a make or break in theswitch.

When the switch is mounted as to be sub- 40 jected to shocks orvibrations the construction must be such that the movable electrode isnot caused to flutter in and out of contact with the mercury pool andcause a succession of make and breaks.

Figure 1 illustrates one method to prevent such operation. In thisinstance, the movable electrode is formed-at its extremity whichcontacts the mercury-so thatit rests against the inner wall of the tubewhen the switch cir- 50 cult is open or else is so positioned that thedistance from the electrode to the glass is less than that from theelectrode to the mercury so thatthe amplitude of movement is confined tothat of the shorter distance.

Figure 9 illustrates another method by supporting the armatureindependently of the flexible electrode and causing the movement of {thearmature to flex the electrode, the armature is provided with a forkedextension through which the movable electrode passes, and the weight ofthe armature acts as a stabilizer to prevent vibrations of the electrodeduring those periods in which the circuit is desired open. Whenconstructed in the manner shown, 0.; the armature is not used as .aconductor and the possibility of arcing or unsatisfactory bearing isthereby eliminated.

its free end, in combination with means exterior of said container toactuate said flexible electrode to close the circuit through said fluidincluding a magnet adapted to include said armature within the magneticfield thereof.

2. An electric switch including an elongated cylindrical vertical sealedcontainer, a body of conducting fluid in the bottom thereof, twoelectrodes sealed in the upper end thereof, one entering the said bodyof conducting fluid and the other fluted and flexible throughout theupper portion thereof and terminated out of contact with said conductingfluid, a rectangular armature having curved sides parallel to saidcontainer wall secured upon said electrode below the fluted portion andabove the free end thereof adapted to be flexed by a magnetic fleldexterior of the container to submerge the end of said electrode withinsaid conducting fluid.

3. An electric switch comprising a sealed container, a body ofelectrical conducting fluid therein, a wire electrode including aflexible portion having one end free and normally out of contact withsaid fluid,- a second electrode adapted to make contact with said fluid,a rectangular curved armature mounted upon said first electrodeintermediate its length and spaced .apart from its free end, incombination with a magnet adapted to include said armature within themagnetic field thereof to flex said first electrode and cause its freeend to make contact with said fluid.

4. An electric switch comprising a sealed container, a body ofelectrical conducting fluid therein, an electrode including a flexibleportion having one end free and normally out of contact with said fluid,a second electrode adapted to make contact with said fluid, a pivotedcurved armature within the container in engagement with the free end ofthe first electrode, in combination with a magnet adapted to includesaid armature within the magnetic field thereof to flex said flrstelectrode and ,cause its free end to make contact with said bracing thefree end of said electrode to normally hold the armature in contact withthe free end of said support to stabilize vibra tion of the free end ofsaid electrode.

KARL HUNCIKER...

